Intercommunicating telephonic apparatus.



M. R. HUTUHISON.

INTERCOMMUNIGATING TELEPHONIO APPARATUS. I

APPLICATION FILED MAY 21, 1909.

1,085,916. Patented Feb 3,1914;

4 SHEETS-SHEET l.

WIT NESSES ATTORNEY.

' YINVENTOR.

7 I BY il/ 7 Q? 6/ M M. R. HUTOHISON. INTERCOMMUNIGATING TELBPHONIUAPPARATUS.

APPLICATION FILED MAY 21, 1909.

Patented Feb. 3, 1914.

4 BH|EET8-SHEB$ 2.

WITNESSES: g! INVENTOR. E BY R. HUTGHISON. INTERGOMMUNIGATING TELEPHONIGAPPARATUS.

APPLIGATION FILED MAY 21, 190 1,085,916.

Patented Fe'b.3,1914.

4 SHEETS-SHEET 3.

WITNESSES.-

INVENTOR.

64m By I I 3 w ATTORNEY.

M. R. HUTGHISON. INTERCOMMUNIGATING TELEPHONIG APPARATUS.

APPLICATION FILED MAY 21/1909.

Patented Feb. 3, 1914.

4 SHEETS-SHEET 4.

mm my! m: mans uns on. "darn-yum, \usumcmu. n

i vented certain new and useful Improvements MILLER REESE HUfICHIS ON,

or NEW JERSEY.

INTERCOMMUNICATING TELEPHONIC APPARATUS.

Specification of Letters Patent.

Patented Feb. 3. 1914.

Application filed May 21, ions. Serial No. 497.459.

T 0 all whom it may concern Be it known that I, MILLER Reusellc'rcnison. a citizen of the United States, and a resident of Summit,in the coimty of Union and State of New Jersey, have in- Relating toInterconmiunicating Telephonic .rpparatus. of which the following is aspecititration.

My present invention relates to specialized apparatus for telephonicintercommunication wherein the construction and arrangei-uen-t is suchas to render the apparatus capable of use under adverse conditions ofextraneous mechanical and acoustic vibra tion, or of wind and Weather.

While it will be obvious to those skilled inthe art. that variousfeatures of my invention hereinafter disclosed 'are capable of wideapplication, the general purpose in view h as been the organization ofan etficient telephonic. system of intercommunication forfUlilfiQfltiOnS, battle fields, battle ships, llld-lishllfl l plants,etc, capable of efiicient use under all conditions,espec-ially wheremore or less precise operations or evolutions must be directed orcontrolled under conditi'ons of noise, confusion, or excitement. One ofthe most desirable, and at the same time most trying uses which Icontemplateis thzrt of telephonic intercommunica-tion on a battle shipduring gun tire for the purpose of transmitting orders and impartinginformation as to the direction and time of fire, and particularly astothe rangeand bearing of a hostile shipor other target. When my systemis thus used for fire control on a battle ship, the spotter or rangefinder may be located on the mast or other elevated station of thebattle ship, and he is able to communicate continuously and directly tothe various gun crews the shifting range and other information or ordersnecessary for prompt and eflicient gun fire. He may similarly controlthe direction and time of torpedo fire. In order'that the apparatus mayoperate successfully for such purposes, it is necessary that thetransmitter be capahle of responding to and intelligibly transmittingspeech, notwithstanding the mechanical vibration of the-ship andconcussion and discharge of thevheaviest batteries.

.l prefcr to secure the transmitting and receivlng instrument to theperson of the user. preferably to a head piece. which now be theregulation cap, and l also prefer-ably provide means for concentratingthe sound waves of the voice and carrying them directly to thetransmitter. The sound concentrating means also serves as a shield tokeep out disturbing vibrations. Distinct articulation and cleartransmission of speech may be promoted when necessary or desirable byarranging the sound concentrator and shield so that it will inclose thenasal orifices as well as. the mouth, thus preserving the importantnasal sounds, as well as those of the throat and month. In such case avent should be provided for breathing purposes. This is preferably ofsuch form as to permit ready passage of the air and at the some time tobreak up or smother extraneous sound waves, which might otherwise reachthe diaphragm through the rent, in sullicient volume to interfere withits operation. Thev transmitter is preferably ar ranged to have specialelectrical qualities whereby loud sounds and faint sounds are reproducedat the receiver equally well. That is to say, the transmitter ispurposely so constructed as to distort speech by nuignh tying thesibilants, .low sounds, and overtones, while decreasing the effect ofthe louder sounds and fundamentals. Such a transmitter is especiallydesirable because it commonly happens that under the nerve rackingconditions of battle or even of target practice, the spotter willunconsciously raise his voice to such an extent that an ordinarytelephone apparatus would respond only with an unintelligible roar atthe re ceiver. On the other hand, it may happen that during times oftrying service, the operator may be forced by physical weakness orsuliering from wounds, to speak so low that his voice would be inaudibleor unintelligible with the ordinary apparatus, whereas my apparatus willsatisfactorily work under both conditions The transmitting and receivingsets may be wired up to each other and to the battery in any known ordesired way, but I preferto connect the transmitter of the observationor controlsta tion in with the receiwer of the; gun

rear electrode of the transmitter.

crew stations, and provide parallel branches having transmitters of thelatter in series with the receiver of said central station.

Havin briefly explained some of the purposes an% features of myinvention, I will now proceed to describe in detail certain usefulembodiments thereof, having special reference to the accompanyingdrawings, wherein Figure 1 is a side view of a desirable form oftransmitter and receiver set secured upon the person of the operator inposition for use. Fig. 2 is a side elevation of the transmitter andsound concentrator, showing in vertical section the' sound excludingconstruction of the breathing vent. Fig. 3 is a similar view showingmeans for equalizing concussion and other, stresses on the front andrear sides of the transmitter diaphragm. Fig. 4 is an axial sectionaldetail of'the transmitter. Fig. 5 is a face view of the Figs. 6 and 7are detail views of modified arrangements of transmitter electrodes andthe microphonic carbon balls. Fig. 8 is an axial sectional view of thereceiver. Fig. 9 is a face view of the receiver with the diaphragmremoved.

It will be understood that while the said drawings and the descriptionthereof con tained herein, disclose with considerable particularitycertain specific forms in which my invention may be usefully embodied,it will be understood by those skilled in the art that variousomissions, substitutions, and changes in the forms, proportions, sizes,and details of the device and of its operation, may be made withoutdeparting from the spirit of my invention.

In Fig. 1 I have shown the receiver and transmitter with soundconcentrators and wiring mounted in a convenient manner upon the headpiece or cap of the user, in such manner as to leave the hands free formanipulation of range finders and other instruments, while the field ofvision is unobstructed. I preferably utilize the regulation cap as thesupport for these instruments, since it is very desirable that the headand eyes of the observer be not deprived oi their customary protection.1 The band 1, of metal or other sultable material, is secured to the cap2 by a clamp nut 3, screwing upon bolt 4, projecting through slot 5.Where desired, the band may also be provided with supplemental securingmeans, as, for instance, by stitching as at 6, To the band 1 areadjustably secured the transmitter supports 7 7 and receiver supports 8,8, for holding toe transmitter 9 and receiver 10 in position to fit thehead contour of the operator.

Each ransmitter support 7 7 is adjust ably secured by a nut 11 on screw12, which extends from the band 1, through slot 13.

The point of this connection is near the rear of the vizor of the capand preferably at or near the vertical plane of the temples of thewearer. The slot and screw-nut connections permit of vertical as well asangular adj ustment of the supports 7, 7. A brace 14 is preferablypivoted at 15 to the transmitter support 7, and adjustably held byclamping nut 16 on screw 17, extending through slot 18 in said brace 14.The not 16 and screw 17 are preferably utilized for the further purposeof securin the receiving support 8 in its desired position. This support8 is also capable of vertical and angular adjust? ment by reason of theslot 19, which engages said screw 17. The various supports and bracesare preferably of spring metal.

The transmitter support 7 extends downwardly, preferably across thecheek bones, to about the region of the mouth, and thence forwardly andinwardly to the transmitter 9, which is pivotally clamped between theends of said supports 7., In order that the pivotal connections may besecurely locked against rotary displacement, I prefer to employ apositive locking connection, such as is shown in Fig. 4. In said figure,the pivotal screw studs 20, 20 are rigidly screwed into the transmitterand washers 21, 22, having engaging faces toothed as at 25,;1reinterposed between the transmitter supports 7. 7 and the transmitter 9.The washers 22, 22 are locked against rotary motion with respect to thetransmitter by means of the eccentric studs 23, 23, and the washers 21,21 are rigidly held with respect to the support 7, 7 by being brazed orotherwise secured thereto. The washers 21, 21. and washers 22, 22 beingthus nonrotatably fixed to their respective members, the parts may belocked in any desired angular relation by simply screwing up the nuts24.

The shield 26 for concentrating the voice of the operator and forexcluding extraneous sounds, is secured to the trans mitter 9 in anydesired manner. A con venient arrangement for this purpose consists ofan annular clamp, comprising a screw ring 27, provided with an annularrecess 28. screwed into clamping engagement with a flanged ring 29.These two rings have clamped between them a head 30. formed or molded onthe cylindrical end of the sound concentrator. The two clamping membersthus secured to each other, are then secured over the mouth of thetransmitter by a screw threaded extension 31 of the annular ring 29.

The sound concentrator may be formed of soft lead, and may be edged withrubber or leather to form a face engaging portion. Preferably, however,the entire concentrator is formed of rubber of suitable texture. Ineither case, the concentrator is preferably the breathing of theoperator.

circular in cross-section hi the transmitter end, and at the, other endformed so. as to, fit the mouth and'nose of theoperator. When formed soas to include the nose, I prefer to provide a breathing vent, as shownin Fig.

so. that the apparatus may remain permanently in position withoutinterfering with In order that. there may be free flow of air withoutrendering the device inoperative by reason of violent noises of gunfire, etc, such as.

would readily pass an unprotected opening, I prefer to employ some such.arrangement as shown in Fig. 2. In this figure, the opening 32 in theconcentrator 26 is surrounded by an annular flange 33, provided with ascrew threaded projection 34. of smaller diameter, upon which is screwedthe clamping ring nut Secured to the inner face of the screw threadedprojection 31', is a downwardly extending open ended cylinder 3.6.Outside of the cylinder 36 and concentric therewith, is secured a largercylinder 37, closed by a bottom 38, adj acentt-he lower end of cylinder36, and provided with ventilating openings 39. at points remotetherefrom. By this arrangement ample. space. is afforded for ingressand, egress of the air necessary for breathing without the possibilityof developing a. tendency either to a vacuum or a plenum in the soundconcentrator, at the same time extraneous sound waves are broken up bythe perforations 39 and the labyrinthian walls 37, 38, 36.

The. internal construction and the microphonic qualities of thetransmitter are especially designed and adapted for the urpose oftransmitting speech intelligibly, whether emitted as a, shout or as awhisper.

Heretofore, in my work on transmitters for making. speech intelligibleto the deaf, l have succeeded in producing transmitters which areextremely sensitive to normal sounds, and entirely unresponsive to veryintense sounds, but the specific method of.

operation whereby this result was achieved renders it, impossible toapply the deaf machine microphone to my present purposes, unless oruntil modified in accordance with. my present discovery and invention.In the deaf machine microphone, I use a small ranged a thin arbondiaphragm connected as the front electrode of the microphone. Thecavities, the surface of the diaphragm adjacent thereto, and balls. orspheres-arepoli ed. When this am.

referably also the.

rangement of carbon block diaphragm and balls 15- placed; in a. verticalposition, the

the balls or spheres tend to roll out of the cavities against thediaphragm, thereby pro riding a loose and very sensitive microphonecontact. An important feature of this prior construction is that thehemispherical ravities are grouped ina relatively small area at oradjacent the center of the diaphragm where its amplitude of vibration isgmatest, the greater proportion of the area of the diaphragm toward theperiphery being left unprovided with microphonic contacts. \Vith themicrophonic contacts comparatively localized adjacent the center of thediaphragm, a loud, noise or a strong vowel sound causing great amplitudeof vibration of the diaphragm causes the carbon balls to jump or movebodily so as to de" st-roy their bridging relations with the diaphragmand carbon block, thereby rendering. such balls inoperative so far asconcerns the functions of microp honic amplification of speechvariations. On the other hand, the whispering sibil-ants. and

faint overtones permit the. balls to remainin their microphonic positionand condition wherein they most efiiciently magnify the faintervibrations. I, have discovered that this restricted arrangement of thecavities near the center of the diaphragm, is comparatively useless formy present purpose, because under practical conditions of battle, wherethere are tremendous .vextraneous sound vibrations and where theoperator is liable to shout into the transmitter, the vibrations at thecenter of the diaphragi'n are frequently great enough to drivepractically all of the balls at the center out of operative microphonicrelation to the front and back electrodes, thereby rendering thetransmitter temporarily useless. I; have discovered, however, that byincreasing the diameter of the back electrode and by pro-. viding anextended area of hemispherical cavities suit-ably distributed overthe-area toward the periphery of the diaphragm, there will always be anadequate number of cavities whereof the balls are agitated to just therightv extent to produce the best microphonic effects. This will beevident from the fact that the amplitude of vibration of the diaphragmis greatest at the center and is progressively less outwardly from thecenter. It follows that for ordinary conditions of very slight vibrationof the diaphragm, the balls near the center will vibration of thediaphragm increases by reason of a louder sound, the microphoniccontacts at the center will gradually go out of operation, while thosetoward the periphery begin to he agitated just enough to produce thebest microphonic action.

From the above it will be seen that one of the features of my inventionconsists in so distributing the microphonic contacts over the face ofthe diaphragm that. there will always be active regions of maximummicrophonic amplification no matter how great may be the vibration ofthe diaphragm at the center.

I may have microphonic contacts at the center of the diaphragm, as Wellas toward the periphery, in order that faint whispers may beinteiligibly transmitted, but as between the two, the contacts away fromthe center are on the whole more important, and in certain cases, I mayarrange the contacts in an annulus with none at the center of thediaphragm. {There seems to be a certain annular region a slight distanceinward from the periphery, where widely varying intensities of speechseem to produce approximately equal vibratory displacements, so thatwhen the microphonic contacts are arranged in this annulus, the softsounds are magnified and the loud sounds decreased to approximateequality.

I have found that it is desirable to use a large number of balls andspheres over a large area of the diaphragm, and by dividing'them thusinto small groups in separate cavities. can obviate the tendency to packwhich exists in granular carbon transmitters. wherein a comparativelylarge body of granular carbon is used with electrodes of large area andthe device is used with the diaphragm in a vertical position.

The. above principles of operation are embodied in the arrangement shownin the drawings, particularly in Figs. 4 and In said figures is shown :1back electrode cup or support 40. which may be a brass or aluminumcasting. formed with a cavity 41, con tainiug the carbon blockconstituting the back electrode 4-2. This carbon block is held inposition within the cavity by bolts 43, having heads 44 countersunk orrecessed in the face of said block and the shanks extending through theback side of the casting 4-0. As shown in the drawing, insulatingbushings and washers, as at 45, are employed. Two of said bolts areconnected by a conducting bridge piece 46, to which is secured, bysoldering or otherwise. one of the terminals 47 of the line connections.These parts are held in place by nuts 48. The micro phonic cavities 49,containing the microphonic balls or spheres 50, are formed in the frontface of the back electrode 4-2. These cavities may be distributed overthe face of the electrode somewhat after the manner inannular zonestaken at suecessivelyincreasing distances from the center of thediaphragm. show a progressively increasing microphonic area extendingwell out toward the periphery of the diaphragm.

The casting 40 is formed with a plain annular seat 51, upon which restsa thin sensitive carbon diaphragm The block 2, washers 45, and casting40 are so proportioned and relatively arranged that the diaphragm 52 issubstantially parallel with the front face of the back electrode 42 andis separated therefrom by a space only sufficient to permit of themaximum desired vibration of the diaphragm. The balls or spheres 50 aremade large enough so that they will not escape from their cavities andbecome lodged between the face of the diaph agm and the block. even whenthe diaphragm vibrates at itsmaximum amplitude. The thin carbondiaphragm which I find to be the best for articulation, is exceedinglyporous and absorbs moisture from the air very quickly. The etlect ofthis when passing considerable current as is necessary for satisfactoryoperation, is to produce whistling sounds in the transmitter, which tendto obscure speech and thus impair the effectiveness of the system. Formy present purpose. l tind it necessary to protect the diaphragm fromall moisture. To this end, it may be covered with a layer of waterproofvarnish. but. under conditions of constant use and vibration, suchwaterproofing is liable to break down. Moreover, the-amount of varnishor other material necessary for the purpose considerably increases theweight of the diaphragm, thus adding to its inertia and increasing itstime period. This necessitates using a thinner diaphragm for a givenperiodicity and the thinner the diaphragm is, the weaker and more liableit is to be broken by shocks or concussions imparted either byaccidental blows upon the case or by discharge of heavy artillery.Moreover. if the diaphragm is made thin, the waterproofing material,which i'susually more or less nonconducting, is liable to permeatethrough to the rear side of the diaphragm and impair its efficiency as amicrophone. For the above This acts fairly well for a time,

and other reasons, I prefer to protect the diaphragm, whether waterproofor not, from all possible access of moisture, as well as from mechanicalor acoustic abuse, by an ranging a thin sensitive diaphragm preferablyof non-corrosive metal, such as Tobin bronze, in front of said carbondiaphragm 52. Over the carbon diaphragm 52 is placed a cork Washer 54,which in turn is clamped in place by washer 55, forced into the casting40. Upon' this rests the diaphragm 53. which in turn is clamped in placeby the -washer 56. The washer 56 is secured in 65 dicated in Figfd,wherein it will be seen that I place and the joint rendered water tightby we 51'. The supplemental diaphragm protects position, as in Fig. l,for otherwise the brittle; moreover, it is close to the rear electhecarbon diaphragm from moisture of the breath or of the weather, and thespace between the diaphragm serves as a cushion to protect the carbondiaphragm from the effects of acoustic concussion. \Vashers 56 and 54-may be of brass instead of cork. if desired.

'lhemouth piece 26, heretofore referred tn, may be of the conventionalform commonly employed. upon telephone transmitters, but it ispreferably formed as a complete shield to inclose both mouth and nose.In the latter case, it is cut away to fit the face and sides of the noseof the operator, thus concentrating the sound of his voice, excludingextraneous sounds, and also in case of bad weather, excluding rain orspray. If formed of lead, this shield may be bent or made so as to fitthe face of the'particular individual who is to use it, but I prefer toform the face fitting portion of the shield of soft rubber, so that itmay be readily deformed and. forced" into contact with theirregularities of the face, without causing unnecessary physicalinconvenience to the wearer.

the conditions of actual useof the transn'iitterin the manner abovedescribed, require that the operator be free to look upward or downward,it is desirable that the transmitter be somewhat inclined forwardly whenthe operators face is in the normal inicrophonic balls would rollbackward into the cavities 49 out of contact with the diaphragm 52whenever the operators face is turned downwardly. This brings the ballsor spheres to the position shown in Fig. 6.

In certain cases the transmitter may be adapted for use throughaconsiderable range of rearward inclination by forming the cavities onan upward slant, as shown at 59, in Fig. 7 'With this construction, thetransmitter may be arranged with its diaphragm normally vertical and yetthe operator may turn his face downward through a considerable anglebefore the balls 50 will roll out of operative engagement with thediaphragm 52.

The carbon diaphragm is more or less f1 ail. and under unusual stressessomewhat trode. 42. Hence, durability and sensitiveness both requirethat the atmospheric pressure on both sides of the diaphragm be ap--proximately the same. To this end, I. may utilize the arrangement shownin Fig. 3, wherein a passage 60 communicates from the front side of thediaphragm to a screw threaded nipple 61, terminating in a bag 62, whichserves as a reservoir of air at atmospheric pressuresmThisbag ispreferably of'thick' flexible rubber which will not transnected to theline conductors by suitable mit exterior air vibrations nor permit theentrance of moisture. A similar passage 63 leading from the rear side ofthe diaphragm, connectsfwith a screw threaded nipple 64, terminatingin aflexible bag 65, similar to 62. it will be obvious that the nipples 61,

.64, might communicate with a single bag or flexible passage, or thepassages 60, 63 might be joined directly. The latter expedient wouldequalize thepressure on both sides of the diaphragm, but would notmaintain the diaphragm cavity itself at the same pressure as that of theexternal atmosphere.

The space 66 at the rear of the casting 40 and between it and .thetransmitter case 9, may he filled with an insulating compound of thecharacter employed in the art for such purposes. A composition suitablefor the purpose should be such as may be liquefied by heat so that itcan be poured into the cavities and will harden upon cooling. There aremany composition of this class employed for insulating induction coils,transformers, etc.

For a receiver, I may use any known or desired instrument, such as maybe purchased in the open market. It should comprise an electromagnetconsisting of iron cores 70, 70, energized by coils 80, 80, conmeans,such as wires 81, 82. The diaphragm 83 may be secured in placevby cap84, screwed down on vthe washer 85. The conducting connections arepreferably soldered in place as at 86. 87 and the case is then. filledwith hardened insulating compound 88, which may be of the generalcharacter above described. This conventional receiver case may bemounted for my purposes in an eX- terior case 10,which is formed with aninwardly projecting flange 89, closely fitting the receiver case andserving as a clamping member for engaging the edge of the flange orscrew cover 84. The other member of he clamp is formed by screw ring 89hav- 1,10 ing an inwardly projecting flange pressing upon the out-erface of the cover 84, through an intervening washer 90. The case 10 isformed at its front edge with an annular recess 91, engaging av head 92,formed or molded upon a shield or concentrator 93,- adapted to fit overthe ear and against the head so as to exclude water and extraneoussounds after the manner of the mouth and nose piece previouslydescribed. The shield 93 is preferably of soft rubber.

The case 10 is secured to the support 8 previously described, in anydesired way, preferably by a universal joint, which will permit the headengaging shield; to' accommodate itself to the person of the wearer.

As shown in the drawing, the stud 94 is riveted as at 95, to the centerof the back of the case 10.. This stud has a spherical outer head 96,fitting a spherical socket, shown 13,0

as consisting of oppositely concaved clamping members 97, 98, which areheld in ad-- justable frictional. engagement with the sphere 96 by meansof the screw 99.

The upper endof the support 8, slotted as at 19, may be adjustedvertically and angularly by loosening the nut 16. The. angu-- laradjustment is maintained by positive interlocking engagement of washershaving tooth engaging faces similar to those shown at 21, 22, Fig. 4. Inthe present case, the washer 100 is brazed or otherwise secured to'theband 1 and the washer 101 is held from rotation with respect to thesupport 8 by means of a key or spline projection 102 extending into theslot 19. Similar washers are used to lock support 7 to band 1.

The above transmitter and receiver outfit meets all the/practicalrequirements for a telephonic fire control system on a battleship. Theman-who is operating the range finder has his vision unobstructed in alldirections, his head is not limitedas to its movement relatively to thebody, and yet he may telephone continuously his ranges and otherinformation at the very instant his observation is made. He does nothave to dispense with the protection from sun or rain afforded by a cap.The line conmotions are out of the way where they do not embarrass anyof his movements.

With the above described outfit, one or both of the receivers may bedisplaced to leave one ear free, or permanently removed so as to leaveone ear free at all times;

Similarly, the outfit may be adapted for use in a turret or at the gunsby displacingor removing the transmitter and retaining only thereceiver. In either case, the entire outfit may be removed instantly byremoving the ca As as been suggested above, my telephone outfits may beused in any desired systems of circuits. If desired, the two receiversmay be included in independent systems so that the operator may bothtransmit and receive in one system while the other receiver, connectedin another system, permits him to hear all orders that are given in thatsystem.

It will be noted that there is a special advantage in my arrangement ofa pair of telephone receivers in combination with a transmitter held infront of the mouth. The band encircles the head above the eyebrows andhence is not positively clamped against removing or tilting, yet theweight of the transmitter carried by said band in a position in front ofthe mouth of the user affords a certain amount of leverage tending totilt the band upwardly at the rear. This tendency is resisted by havinga pair of sup ported receivers encircling the ears and resilientlyclamping the head between them. The clamping action tends to resistremoval and inclusion of the entire ear within the cavity tends toafford a semi-positive lock tending to resist removal.

My sending and receiving sets and the wiring constituting myintercommunicating system, as described above, may be so de' signed,constructed, and installed as to con stitute a practical fool proof,waterproof outfit, adapted to stand the roughest usage and to operatesuccessfully under the most trying conditions without interference ofextraneous sounds, however violent, and to remain in perfect operatingcondition for an indefinite length of time in any climate.

The head gear for supporting the telephone set may be made ofnoncorrodible material, such. as gutta percha, rubber, copper, brass, orbronze, orif desired spring steel having a copper welded coating may beused. A satisfactory quality of duplex metal for such'purposes is now acommon article of manufacture and sale. The exterior transmitter andreceiver cases 9 and 10 may be made with a copper face welded to theiron M back. The connecting wires may all be soldered permanently inplace and the empty spaces in the transmitter and receiver cases may befilled with insulating material. These cases are preferably of a singlepiece of noncorrodible metal formed .without joints or seams, and allperforations therein may be hermetically sealed, either by saidinsulating material or otherwise. Only one of the line connections needextend within the case, since the case itself maybe utilized as part ofthe return circuit, if such arrangement is considered desirable. Theclosure of the open end of the microphone case may be made perfectlytight by forming the rings 55, 56 of brass or copper and forcing theminto the block 40. The encircling walls may then be upset and forcedinto most intimate engagement with said rings by lateral action of thetool at the time the lip 57 is spun over the front face of the ring 56.The formation of the ring 27, whereby it bears upon the outer face ofthe ring 56, serves the dou- -ble function of a frictional lock to holdnonconductors of sound. These will be such marine work, as wellas foruse on ship board and in coast fortifications, wherethey are exposed tosalt sea air and oftentimes to driving storms.

The shields constituting'the mouth; and ear pieces may be'of suchmaterial, texture, or construction as will render them efiicient as toprevent-collapse under the moderate pressure necessary to hold themiu'contact with the head of the wearer. Toward the face engaging edges,they may be of soft rubber, as nearly pure rubber gum as may be desired.The. face engaging portions gaging cushion. The transmitter shield is ofsuch length as to permit the vocal vibrations to become fully developedas elastically propagated waves before they reach the diaphragm, and theWalls b'eing nonresonant, will prevent any confusing reechoing effects.The receiver'shields should be of the same general structure'in thatthey should be stiff enough to prevent a tendency to collapse whenpressed inwardly, as this mig'ht tend to produce a capping e'fiect, wh,ich

would convex the ear drums and impair their sensitiven'ess. vThe ha r ofthe head will ordinarily prevent this efiect from becoming prominenhgbutin certain cases I propose to secure a very sound proof fit of theseshields by shaving-the hair about the ear or plastering it withVaseline. In'su ch case, a valve or vent" may be arranged to permit ofequalizing external and internal pressure whenever theoperator isinconvenienced from internal'pressure or vacuum. For many purposes theface engaging portion need not fitthe face perfectly, except where usednear discharging guns or similar source of violent air .waves.

The lmicrophoneiof the transmitter is a' v loud speaking. microphoneinsomuch as it magnifies the slighter sounds, thereby producing in thereceiver the' effect of a comparativelyloud voice. At the same time thereally loud sounds at the transmitter are suppressed or greatly reducedin the receiver- The arrangement of circuits shown is well adapted foruse in connection with such" a transmitter insomuchasthe transmitterofthe person speaking-is not directly in series wlth h1s own receiver,thelatter being ina parallel eircuiting; containing the trans mitter ofthe other station; From this ar-- rangement it resultsthatthegpersonspeak 6' ing isnot'subjectito the disagreeable-effect. B

of shouting in his own ear, whichwould remands and exigencies. of thevarious situasult from. a series connection with his own transmitter,and at the same time the outgoing variations are conducted directly tothe receiver at the other station without bemg weakened by theresistance of another receiver in the same circuit. Itwill be understoodthat the vibrations in-each of the parallel circuits .afi'ect the othersufiiciently so that each speaker will-hear his own voice I in his ownreceiver sufilciently to know that the lineis not dead.

The qualities of the microphone make the apparatus suitable for generaluse in communicating with deaf persons and the trans mitter and receivershields are capable of use in situations where-a sound proof telephoneboot-h or cabinet is impracticable.

. The various advantages of my waterproof, extraneous sound proof,inter-communicating telephone system willbe obvious to those skilled inthe-art, andthe various modifications and omissions of parts for whichit is readily adapted will be suggested and contrdlled by the peculiardetions and conditions in which it is to be used.

What]: claim is: 1. A. telephone set comprising a cap orhead piece, atransmitter, and a receiver, in combination with transmitter andreceiver supports secured to said head piece and connected to saidtransmitter and receiver to hold the same-in predetermined relation tosaid head piece, said transmitter being pro-1 vided with asound]concentrating shield 0o adapted to fit the contour-ofthe face of thewearer, and a breathing vent in said shield, said breathing jvent beingprovided with asound mufliing device, for the purpose described. I

2. A telephone set comprising a cap or head piece, a transmitter, andareceiver, in combination with transmitter and receiver supportssecuredto said head pieceand connected to said transmitter and receiverto hold the same in predeterminedrelation to. said head piece, saidtransmitter being pro?" "vided with a sound concentrating shield adaptedto extend about the mouth and nasal opening of the faceof the user, anda breath- I 3. A telephone set comprising a band-and a binding screw foradjusting the circumferenti'al extent. of said band, in combination withtransmitter and receiver supports adjustably secured to said band bybinding screw connections, a brace extendlng from one support to theother, the screw conncction for one support being utilized for.

clamping the brace in place, substantially as describe 4:. A telephoneset comprising aband and a binding screw for'adj usting the circumfer-15c ential extent of said band, in combination with transmitter andreceiver supports adjust-ably secured to said band by binding screwconnections, a brace pivoted to one support and extending to the other,the screw connection for one support being utilized for clamping thebrace in place, substantially as described,

5. A combined transmitter and receiver support, comprising a strip ofmetal, separate screw clamps secured thereon, a transmitter support heldby one of said screw clamps and a receiver support held by the other ofsaid screw clamps, in combination with a slotted brace pivoted to saidtransmitter support below said first mentioned screw clamp, and formedat the other end with a slot extending into operative engagement withthe screw clamp of the receiver support for the purpose described.

6. A, combined transmitter and receiver support, comprising a strip ofmetal, separate screw clamps secured thereon, a trans mitter supportpivoted at one of said screw clamps and a receiver support pivoted atthe other of said clamps, in combination with an adjustable bracepivoted to said transmitter support below said first mentioned screwclamp, and extending into operative engagement with the screw clamp ofthe receiver support, substantially as described.

7. In a telephone head set for combined telephone transmitting andreceiving, a band adapted to be secured about the head of the operatorabove the eyes in an approximately horizontal position,two telephonereceivers, resilient members for supporting said telephone receiversfrom said band so as to elastically Copies at this patent may beobtained for five cents each, by addressing the "Commissioner ofPatents,

weenie clamp the sides of the head at points opposite the ears andthereby resist removal or shifting of position of said band when inplace upon the head of thewearer; and a telephone transmitter supportedfrom said band in a predetermined substantially rigid position in frontof the mouth of the wearer, whereby tilting or leverage etiect of saidtransmitter on said band, is resisted by the clamping action of saidreceivers.

8. In a telephone head set for combined telephone transmitting andreceiving, a band adapted to be secured about the head of the operatorabove the eyes in an approximately horizontal position, two telephonereceivers, resilient members for supporting said tele phone receiversfrom said band, so as to elastically clamp the sides of the head atpoints opposite the ears and thereby resist removal or shifting ofposition of said band when in place upon the head of the wearer, atelephone transmitter, and supports extending from said band to saidtransmitter and disposed out of the line of vision of the wearer, saidsupports holding said transmit ter in a predetermined substantiallyrigid position in front of the mouth of the wearer and movement of saidtransmitter being resisted by the clamping action of said receivers.

Signed at New York city, in the county of New York and State of New Yorkthis sixth day of October A. D. 1908.

MILLER REEQ'E HUTCHISON.

Witnesses:

GEORGE C. DEAN, IRVING M. Onnmcrrri Washington, D. G.

